Range and altitude calculator for use with echo ranging training equipment



M. RANGE AND ALTITUDE CALCULATOR FOR USE Feb. 10, 1953 E; DROZ WITH ECHO RANGING TRAINING EQUIPMENT 4 Sheets-Sheet 1 Filed June 1 1951 INVENTOR HARGEL 5 M02 ATTORNEYS Fe 1953 M. E. DROZ 2,627,673

RANGE AND ALTITUDE CALCULATOR FOR USE WITH ECHO RANGING TRAINING EQUIPMENT Filed June 1, 1951 4 Sheets-Sheet 2 RELATIVE COMPONENT O SPEEDS ANGULAR DISPLACEMENT OF DISKS 49 8 51 INVENTOR MARCH. E. 0802 ATTORNEYS Feb. 10, 1953 M. E. DROZ 2,627,673

RANGE AND ALTITUDE CALCULATOR FOR USE;

WITH ECHO RANGING TRAINING EQUIPMENT Filed June 1, 1951 4 Sheets-Sheet 3 INVENTOR MAROEL E. DROZ ATTORNEYS Feb. 10, 1953 M. E. DROZ 2,627,673

RANGE AND ALTITUDE CALCULATOR FOR USE WITH ECHO RANGING TRAINING EQUIPMENT Filed June 1, 1951 4 Sheets-Sheet 4 INVENTOR MARCEL E. DROZ ATTORNEYS Patented Feb. 10, 1953 UNITED STATES PATENT OFFICE RANGE AND ALTITUDE CALCULATOR FOR USE WITH ECHO RANGING TRAINING EQUIPMENT Original application August 21, 1946, Serial No. 692,021, now Patent No. 2,558,425, dated June 1951, Serial No. 229,330

4 Claims.

The present invention relates to mechanical equation solvers and more particularly to range and altitude calculators for use with echo-ranging training equipment.

The present application is a continuation in part of my application, Serial No. 692,021, filed August 21, 1946, for Equation Solver, now Patent No. 2,558,425 of August 26, 1951, and directed to divisional subject matter of my above-identified prior application.

When training operators for echo-ranging equipment, it is inconvenient, expensive, and time-consuming to employ actual instruments in normal operation, which would require ships and airplanes. It is therefore a practical necessity to employ a simulator to produce similar indications to those which would be encountered in actual operation by means of small apparatus which may be conveniently located at a training station. The training equipment must be capable of converting the movements of a simulated target in space into polar coordinates relative to the simulated position of the echo-ranging equipment, since echo-ranging equipment produces indications of the azimuth, elevation angle and range to a target.

The present invention is directed to a device for producing voltages proportional to the azimuth, range and elevation angle of a simulated target relative to the simulated echo-ranging position suitable for application to conventional radar control equipment.

An object of the present invention is to provide a mechanical system for producing voltages representing the polar coordinates of a simulated target from a simulated radar position.

It is a further object of the present invention to provide a mechanical system wherein movements of a simulated target are reproduced as varying voltages representing polar coordinates of the simulated target from a predetermined point in space.

It is a still further object of the present invention to provide a mechanical system for producing voltages representing polar coordinates of a target from a predetermined point suitable for operation of radar control equipment.

Further objects and advantages of the present invention will be made readily apparent to those skilled in the art by reference to the following description and to the appended drawings in which:

Fig. 1 is a diagrammatical showing of the loca tion of a target relative to a fixed point;

Fig. 2 is a prospective view of a preferred modification of the present invention;

Divided and this application June 1,

Fig. 3 is a plan view of a mechanical resolver for converting a speed vector into rectangular components of the vector;

Fig. 4 is a diagram illustrating the operation of the resolver of Fig. 1;

Fig. 5 is a prospective view of the system for integrating rectangular speed components into a position indication of the present invention;

Fig. 6 is a prospective view of the system for converting a position indication to a polar coordinate system relative to a point used in the present invention; and

Fig. '7 is a plan view of the polar coordinate system shown in Fig. 4.

Referring now to the drawings, there is diagrammatically shown in Fig. 1 the trigonometry involved in the polar location of an aircraft A relative to a fixed station B. The speed of the aircraft A is represented by the line V, and the direction of movement of the aircraft is indicated by the angle c. The ground range r of the aircraft A relative to the fixed station B at any time t is given by the following equation:

where X0 and Y0 are respective rectangular coordinates at to. The azimuthal bearing 0 of the aircraft A relative to the fixed station B is given by the following equation:

The simultaneous solution of these equations will give the polar coordinates of the aircraft A in a horizontal plane, but neglects the altitude L of the aircraft. Where the altitude of the aircraft is included, the slant range R of the aircraft and the elevation angle a are given by the following equations:

A mechanical solution of the above equations is achieved by devising a dynamic scale model which actually duplicates the relative movements of the aircraft A as shown in Fig. 2, wherein the movements of the block ll correspond to the movements of the aircraft and the fixed station B corresponds to the column 13. The speed of the aircraft is applied to the device by means of the variable speed motor IS, the speed of the motor being controlled in accordance with the assumed speed of the aircraft A. The resolver ll converts the rotation of the motor l5 into two components, one representing movement in an east-west direction varying with the sine of the angle applied to the shaft l9 and the other representing movement in a north-south direction varying as the cosine of the angle applied to shaft 2!.

The rotation of the shafts l9 and 2! are employed to move the carriage 23 by a system to be later described, and the carriage 25 is mechanically connected to the carriage 23 by means of the post 27, so that the carriages remain one above the other as the carriage 23 is moved. The carriage 25 moves on the parallel revolving tracks 29 which are pivoted about the column [3 so that the angular position .of the revolving tracks 29 corresponds to the angle 0. A second electric motor 31 carried by the carriage 25 drives the threaded rod the threaded rod 33 being perpendicularto the revolving tracks 29 and carrying the block I l thereon. The block 35 is pivotally connected to the block I! and contains a hole to slidably receive the rod 3? which is pivoted electric motor I5 drives the disc -39 which is frictionally engaged with the disc 3!, the disc 4| being frictionally engaged with disc 33 of the same diameter, so that discs ll and 43 revolve at the same speed which is proportionate to the speed of the disc 39. The wheels '45 and 31 bear on the plane surfaces of discs ll and 33 respectively, and are driven at speeds proportional to the radial displacement of the respective wheels from the centers of the discs. The radial displacements of the wheels 45 ands? are controlled simultaneously by means of the Scotchyoke connections now to be described.

The discs 59 and 5| having the same diameter are mounted above the discs 4 I, 53 and the wheels 55, 5?, and are interconnected by the disc 53, so that the discs 49 and 5! revolve in the same direction and at the same speed. Attached to the discs 49 and 5| are the pins 55 and 57 which engage the Scotch-yokes 59 and GI respectively, so that the Scotch-yokes move toward and away from the centers of the discs ll and 43 in simple harmonic motion when the discs 39 and 5| are revolved. The wheels 55 and B! are attached to the shafts l5 and 2! respectively which are provided with the collars 53 and 55 engaging the Scotch yokes 55 and 5] respectively.

The distance of the pins 55 and 5? from the centers of the discs 59 and 51 is'the same, and the discs 39 and 5 I, are pivoted over the shafts l9 and 21 at points substantially midway between the centers or the discs 41 and 43 and the edge thereof. the respective centers of discs 55 and. 51 is proportioned to move the wheels 45 and 41 equal distances on either side of the center ..of the" discs 4! and 43, so that the speed of. rotation of the wheels varies from a maximum in one direction through zero to a maximum in -thehotherv direction as the discs 49 and 5l are rotated.

The pins 55 and 5'! are angul'arly displaced The distance from the'pinsf55'and 5? to.

from each other by 90, and the relative velocities of the shafts 2i and [9. are respectively indicated by the curves 5? and 65 in Fig. 5. It will be readily apparent to those skilled in the art that turning the discs 45 and 5| will vary the relative rotation of the shafts l9 and 2| in accordance with the sine and cosine respectively of the angular position of the discs. An indicator H is added to the disc 5i to indicate the angular position thereof.

5 shows the portion of the present invention which translates the rotation of shafts l9 and El into motion in a horizontal plane of the carriage The horizontal tracks 73 are arranged parallel to each other, and support the wvheeled trucks l5 and W thereon, the trucks 15,

i? being connected by the parallel movable tracks l5, so that the trucks i5 move in a direction parallel to the tracks 73 with the movable tracks 79 perpendicular to the'tracks id.

The trucks l5, ll are moved along the tracks '15 by means of cables actuated by the shaft 2!. As illustrated herein, the drum 85 is secured to the shaft 2!, and the cable 83 is looped around the drum and secured to the truck 75 after passing through the following circuit: From the attachment 55 on the truck 75 over the pulley 81 to the drum 5i and thence over the pulleys 89, Eli, and 53 to the truck 15. Similarly the cable moves the truck Ti and is arranged as follows:

From the point of attachment 9'? on the truckl'l over the pulley 99 and around the drum 8| in the direction opposite that of cable 83 and thence over the pulleys E5], M3, and H35 to the truck '52; It will be apparent from an examination of Fig. 5 that clockwise rotation of the shaft 25 moves the movable tracks '39 toward the drum 8 l, and vice versa.

The shaft i9 is fitted with a drum l5! having a diameter twice that of drum 8!, and the carriage 23 is moved on the movable tracks '19 by the cable E59 wrapped around the drum I07. The cable E85 follows the following route: From the fixed attachment Hi over the pulley M3 on the truck 5?, the pulley H5 on the carriage 23, the pulley l 57 on the truck Ti, and over the pulley H5 to the drum it? and thence over the pulley I25, pulley l23 on truck 15, pulley K25 on carriage 25, and over pulley 52? on truck 75 to the fixed attachment 29. Clockwise rotation of the rum liil' produces movement of carriage 25 toward the truck ll, and. vice versa at a speed equal to one-half the cable speed in accordance With well-known principles of physics.

ment in the north-south direction.

Referring now to Fig. 6, the rotating tracks 29 are supported by the column 93 and by the circular track 53! by means of wheels I33 mounted on the ends of the rotating tracks. lar track i3! is secured in a position below the tracks 73 and coaxial with the column 53. The carriage 25 is attached to the carriage 23 by means of the post 27, so that movement of car riage23 by the motor 25 moves the carriage 25 to the same position. Movement of the carriage 25 in a direction parallel'to the tracks 29 does The circunot shift the angular position of the tracks, but movement in any other direction imparts angular movement to the tracks 29 and the column I3 with or without movement of the carriage rel ative to the tracks. Thus, any position of the carriage 23 is reproduced as a direction and a distance from the column 13.

The rod 31 is secured to the movable element of an angular position indicator mounted on the column I3, such as the elevation angle potentiometer I35, and the angular position of the rod 31 is controlled by the position of the block II on the threaded rod 33. The length of the threaded rod 33 regulates the simulated altitude of the target and is indicated by the symbol L while the displacement of the threaded rod 33 from the elevation angle potentiometer I35 represents the ground range 1', so that the distance from the block II to the center of the Selsyn transmitter I35 represents the slant range R. There is an error introduced in the device by employing a center such as the elevation angle potentiometer I35 rather than the center of the column I3, but the distance between the two centers is small and the error introduced is small in the actual device. The drawings herein have of necessity been exaggerated in parts to clarify the showing of the device. For example, the altitude L of the target will normally be a small part of the ground range r. The slant range R is indicated by means of a cable I31 attached to the block 35 and wound on the drum I39, the drum being provided with a take-up spring adapted to maintain the cable tight, so that the angular position of the drum I39 is a measure of the slant range R. Gearing MI is provided to reduce the variation in the angular position of the drum I39 to less than a single revolution. Displacement of the block 35 may thereby be readily transmitted by rotation of a Selsyn transmitter I43.

The angular position of the column I3 is indicated by means of the Selsyn transmitter I45, and the column I3 is provided with slip rings I47 which cooperate with brushes (not shown) connected to the radar control equipment. Fig. 7 shows the cooperation of carriage 23 and carriage 25, and the structures interconnecting carriage 25 and the column I3.

In operation, the instructor controls the course of the simulated target by rotation of the disc 5| and the speed of the target by varying the speed of the motor I5, so that the carriage 23 is moved in a fashion corresponding to that of the target. Changes in course and speed of the simulated target may be made at any time, and the position of the carriage 23 is an integration of the courses of the simulated target. The altitude of the simulated target is controlled by the motor 31, and the speed of the motor controls the rate of climb or dive of the target. The instructor may therefore duplicate ordinary maneuvers of an aircraft.

This invention is employed with correlating equipment which compares the position of the simulated target with the position of the students controls, and when the students controls are set in positions corresponding to the positions of the simulated target, produces an indication on the radar control equipment. Several types of such equipment are known to those skilled in the art, and since the correlation equipment is not part of the present invention, it will not be described in more detail.

It should be understood, of course, that the foregoing disclosure relates to only a preferred adjustable speed motor having an angularly,

adjustable control and two output shafts whose speeds vary with the sine and cosine of the angular position of said angularly adjustable control, a first pair of parallel tracks, a second pair of parallel tracks perpendicular to said first pair of tracks and movable thereon in a direction parallel to said first pair of tracks, a carriage on said second pair of tracks movable thereon in a direction parallel to said second pair of tracks, a drum on each of said output shafts, cable means interconnecting one of said drums and said second pair of parallel tracks for movement thereof in a direction parallel to said first pair of tracks, and cable means interconnecting said carriage and the other of said drums for movement in a direction perpendicular to said first pair of tracks, whereby said carriage moves with a velocity proportional to the speed of said adjustable speed motor and in a direction controlled by the angular position of said angularly adjustable control.

2. A system for the solution of radio detection and ranging trainer problems comprising an adjustable speed drive having an angularly adjustable control and a pair of shafts whose relative speeds vary as the sine and cosine of the angular position of said angularly adjustable control, a first pair of tracks, a second pair of tracks perpendicular to and movably supported on said first pair of tracks in a direction parallel to said first pair of tracks, a first carriage movable on said second pair of tracks in a direction perpendicular to said first pair of tracks, a third pair of tracks below said first and second pairs of tracks, a pivotal support for said third pair of tracks, a second carriage movable on said third pair of tracks mechanically connected to said first carriage, a drum on each of said shafts, cable means operatively connecting one of said drums to said second pair of tracks to move said second pair of tracks in a direction perpendicular to said second pair of tracks, and cable means connecting the other of said drums to said first carriage to move said carriages parallel to said second pair of tracks, whereby said carriages are moved in a direction controlled by said angularly adjustable control at a speed controlled by the speed of said adjustable speed drive and the angular position of said third pair of tracks and said second carriage relative to said pivotal support represent the polar coordinates of the position of a simulated target.

3. The device as claimed in claim 2 which includes a rod pivoted from said pivotal support, an axially shiftable shaft carried by said second carriage perpendicular to said third pair of tracks slidably connected to said rod, whereby the angular position of the intersection of said rod and threaded shaft represents the third polar coordinate of a simulated target in space.

4. In a target simulator for use in remote target location training, a first pair of linear tracks, a pivotal support for said first pair of tracks, a first carriage movable on said first pair of tracks, an axially shiftable shaft carried by said first carriage perpendicular to said first pair of tracks, a first adjustable speed drive for axially shifting said axially shiftable shaft, a rod pivoted to said pivotal support for said first tracks connected to said axially shiftable shaft, a second pair of tracks positioned above said first pair of tracks and symmetrically disposed on opposite sides of said pivotal support, a movable pair of tracks perpendicular to said second pair of tracks movable in a direction parallel to said second pair of tracks,,a second carriage movable on said movable tracks in a direction perpendicular to said second pair of tracks and connected to said second carriage, a second adjustable speed drive, a resolver having an angularly shiftable control and two output shafts whose speeds vary as the sine and cosine of the angular position of said angularly shiftable control, a drum on each of said output shafts, first cable means connecting one of said drums and said movable pair of tracks to move said movable tracks in a direction perpendicular thereto, and

second cable means connecting the other of said drums to said second carriage, whereby said carriages are moved in a direction controlled by the angular position of said angularly adjustable control at a speed proportional to the speed of said second adjustable speed drive to simulate the horizontal direction and distance of a simulated target from the trainer as the direction and displacement of said second carriage from said pivotal support and the spacial position of the simulated target is simulated by the intersection of said axially shiftable shaft and said rod from said pivotal support.

MARCEL E. DROZ.

REFERENCES CITED The following" references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,224,182 Crooke Dec. 10, 1940 2,438,898 Campbell Apr. 6, 1948 

